OK this is probably one of the most misunderstood calls in Pb as it rely's on a players perception and possibly sense of fair play.

A ball that appears to land on the 'outer side' of the line can be called out.

The one exception to this rule is the Kitchen line on a serve. The ball must not touch the kitchen line on a serve.

One helpful hint to keep in mind and remind other players is the following:

The contact point of a tennis ball given the same set of circumstances is the size of a silver dollar. The contact point of a Pickleball is the size of a dime. The tennis ball tends to splay or compress on contact, the Pb does not. It is for this reason that many tennis players(ex or current) will call the balls very close to the outer side of the line as good. Whereas, a pickleball player who has read and studied the rules and its' clarifications/explanations will call the same ball out. A good rule of thumb, if the ball lands directly square on the line it is good.

If the ball appears to touch the line on the outer side of the court by say 25% or less the ball is generally out. Hear is where we get to the fairness part of the game.

If a player is not certain he or she should give the opponent the benefit of doubt.

The point to remember is that BoD can come in all shapes and sizes.

Make the best call you can possibly make and accept that your opponents will afford you the same courtesy.